A285810 Primes equal to a centered pentagonal number plus 1.

2, 7, 17, 107, 227, 277, 457, 857, 1627, 3517, 4517, 5407, 9767, 11057, 13877, 15017, 16607, 20477, 23767, 26267, 27827, 35107, 37517, 41927, 42577, 50767, 53657, 58907, 62017, 68477, 79657, 83267, 86027, 93607, 98507, 110777, 113957, 128257, 137477, 145807

Offset: 1

Author

Colin Barker, Apr 27 2017

Keywords

• nonn

Links

• Colin Barker, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000040, A005891, A285809, A285811, A285812.

Programs

PARI

cpg(m, n) = m*n*(n-1)/2+1 \\ n-th centered m-gonal number
maxk=600; L=List(); for(k=1, maxk, if(isprime(p=cpg(5, k) + 1), listput(L, p))); Vec(L)